JPH0548355Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electron beam lithography device for creating a code plate for a rotary encoder. It is about the mechanism.

[Prior art] A rotary encoder is a disc-shaped plate with a code plate written with a pattern that transmits light attached to a rotating body, and by irradiating this code plate with light, the rotation speed and angle of the rotating body can be determined. This is a device that can measure.

FIG. 4 is a diagram showing a pattern being drawn by an electron beam drawing device on a code plate used in a roller encoder. In the electron beam drawing apparatus shown in FIG. 4, a code plate is arranged on a rotary table rotated by a rotary stepper, and a pattern is drawn on the code plate by irradiating the code plate with an electron beam.

In such an electron beam writing apparatus, it is necessary to adjust the intensity of the electron beam and the beam focus on the code plate. The reason for this is that code plates are usually made of a glass-like flat plate coated with a resist film. This is because the degree of removal varies.

For this reason, the electron beam current and beam focus have traditionally been measured with a Faraday cup to adjust the beam. Normally, this beam is adjusted before writing starts.

Conventional means for measuring electron beam current and beam focus will be explained using FIGS. 5 and 6. FIG. 5 shows a method of measuring the electron beam and beam focus by installing a Faraday cup on a rotary table on which a code plate is placed.

FIG. 6 shows a means for attaching the Faraday cup so that the detection surface of the Faraday cup and the upper surface of the code plate coincide, and moving the whole device in parallel [A to B] when detecting the beam current.

[Problem that the invention attempts to solve]

However, in the method shown in FIG. 5, the upper surface of the Faraday cup is at the same height as the rotary table, and the electron beam is measured at a focal point below the code plate. Therefore, in actual operating conditions, it is necessary to electrically correct by the thickness of the code plate so that the upper surface of the code plate is in focus. However, it is difficult to make accurate corrections, and the problem arises that the beam is not focused on the code plate.

Further, the means shown in FIG. 6 has a problem in that the structure for horizontal movement is complicated and it is difficult to obtain positioning accuracy.

An object of the present invention is to provide an electron beam lithography apparatus for producing a code plate, which is capable of accurately detecting an electron beam with a simple configuration.

[Means for solving problems]

In order to solve the above problems, the present invention includes a rotary table on which the code plate to be exposed is placed;
It is equipped with a rotary stepper for rotating the rotary table, a means for irradiating the code plate with an electron beam, a Faraday cup for detecting the electron beam, and a means for controlling the intensity of the electron beam and the beam focal position by signals from the Faraday cup. The electron beam lithography apparatus includes drive mechanisms 4 and 5 for moving the rotary stepper up and down, a Faraday cup that can be rotated about a rotation axis, a hole in the Faraday cup that can be aligned with an irradiation axis of the electron beam, and and an arm capable of making the surface position of the Faraday cup at the same height as the surface position of the code plate placed on the rotary table.

〔Example〕 Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a sectional view showing an example of the configuration of an electron beam lithography apparatus according to the present invention, FIGS. 2 and 3 are diagrams for explaining the operation of the present invention, and FIG. 7 is a diagram showing an example of the configuration of a Faraday cup. FIG.

1 to 3, the rotary table 2 is integrated with the rotary stepper 1 via a shaft. That is, when a motor (not shown) built into the rotary stepper 1 rotates, the rotary table 2 also rotates.

The rotary stepper 1 itself is moved up and down by a drive mechanism composed of a vertical actuator 4 and a guide 5. That is, the rotary stepper 1 moves along the guide 5 with high precision due to the action of the vertical actuator 4. One of the features of the present invention is that a drive mechanism is provided to move the rotary stepper up and down in this manner. Therefore, the rotary table 2 rotates and also moves up and down.
Note that the final position when the rotary stepper 1 and the rotary table 2 move upward is determined by the guide 5, and the final position in the upward direction (second position) is always determined by the guide 5.
"H" shown in the figure and FIG. 3 is configured to be constant. That is, drawing is performed with an electron beam at this "H" position.

On the rotary table 2 is a code board 3 to be worked on.
is placed. The rotating center of the rotary table has a cylindrical protrusion as shown in the figure, and the code plate is donut-shaped so that the protrusion can protrude.

21 is an arm, and a Faraday cup 20 is provided at the end thereof. This arm 21 has a mechanism capable of rotating around a rotation axis P as shown in FIGS. 1 to 3. When the arm 21 is rotated, the hole 72 of the Faraday cup can be aligned with the irradiation axis of the electron beam A, as shown in FIG. Furthermore, at this time, the surface position of the Faraday cup is adjusted to the rotary table 2 as shown in FIGS. 2 and 3.
It is configured to be at the same height as the surface position H of the code plate 3 placed above.

The Faraday cup 20 has a structure as shown in FIG. 7, for example. In FIG. 7, 70 is a member made of metal (for example, molybdenum);
1 is a plate made of stainless steel, for example. This member 70 is provided with a hollow chamber 70a,
A plate 71 covers this hollow chamber 70a. On the other hand, this plate 71 has a very small hole 72 (for example, 0.01 mm in diameter) made therein.
For example, a gold film 73 is provided around this hole 72.
is applied. An ammeter is connected to the member 70. In the Faraday cup shown in FIG. 7, when the electron beam A is irradiated into the hollow chamber 70a of the member 70 through the hole 72 of the plate 71, the member 70 is charged by the electron beam. Since this amount of charge is proportional to the intensity of the electron beam current, the intensity of the electron beam can be measured with a connected ammeter.

The beam focus can also be measured using the Faraday cup shown in FIG. The operation is to deflect the electron beam A by an angle θ as shown in the figure.
The gold film 73 is irradiated. Secondary electrons are generated from the gold film 73, and are detected by a device (not shown) to measure the focal position.

The provision of the arm 21 described above is also a feature of the present invention.

The components described above are arranged in a sample chamber 8 surrounded by a case 6 , and the sample chamber 8 is depressurized by a pump 9 .

Further, an electron beam lens barrel 10 is attached to the case 6, and the code plate 3 is irradiated with an electron beam A from this lens barrel 10. Note that even if the electron beam column 10 is attached, the airtightness of the sample chamber 8 is not compromised.

Also, although not shown in Figures 1 to 3,
The electron beam lithography apparatus of the present invention is equipped with means for controlling the intensity and focal position of the electron beam using signals from the Faraday cup. Since the means for controlling the intensity and focal position of the electron beam can be constructed using known means, explanation of an example of its construction will be omitted in this specification.

In such an electron beam lithography apparatus, the intensity of the electron beam and the beam focus are measured in the following manner in order to control the intensity to an optimum value.

First, the code plate 3 is fixed on the rotary table 2. Next, the rotary stepper 1 is moved downward by the action of the vertical actuator 4.

Next, as shown in FIG. 3, the arm 21 is rotated 180 degrees to detect the electron beam. At this time, since the position of the upper surface of the Faraday cup 20 matches the position H of the code plate 3 in FIG. 2, focusing on the Faraday cup 20 is equivalent to focusing on the code plate 3. .

After this beam detection is completed, the arm 21 is rotated 180 degrees as shown in FIG. 2, and then the rotary stepper 1 is moved upward to perform drawing with the electron beam. Of course, in this case, the electron beam irradiated from the electron beam column is controlled to the optimum value based on the electron beam value measured in FIG.

[Effects of this invention]

As described above, according to the present invention, by providing a drive mechanism for moving the rotary stepper up and down and an arm for rotating the Faraday cup, it is possible to detect an electron beam with high precision with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a configuration example of an electron beam lithography system according to the present invention, FIGS. 2 and 3 are diagrams for explaining the operation of the present invention, and FIG. A diagram showing where you are drawing,
5 and 6 are diagrams showing a conventional example, and FIG. 7 is a diagram showing an example of the configuration of a Faraday cup. DESCRIPTION OF SYMBOLS 1...Rotary stepper, 2...Rotary table, 3...Code plate, 4...Upper and lower actuator, 5...Guide, 20...Faraday cup,
21...Arm.

Claims (1)

[Scope of claim for utility model registration] A rotary table on which a code plate to be exposed is placed;
It is equipped with a rotary stepper for rotating the rotary table, a means for irradiating the code plate with an electron beam, a Faraday cup for detecting the electron beam, and a means for controlling the intensity of the electron beam and the beam focal position by signals from the Faraday cup. The electron beam lithography apparatus includes drive mechanisms 4 and 5 for moving the rotary stepper up and down, a Faraday cup that can be rotated about a rotation axis, a hole in the Faraday cup that can be aligned with an irradiation axis of the electron beam, and An electron beam lithography apparatus comprising: an arm capable of making the surface position of the Faraday cup at the same height as the surface position of a code plate placed on a rotary table.